// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

package org.xbill.DNS;

/**
 * Constants and functions relating to DNS message sections
 * 
 * @author Brian Wellington
 */

public final class Section {

	/** The question (first) section */
	public static final int QUESTION = 0;

	/** The answer (second) section */
	public static final int ANSWER = 1;

	/** The authority (third) section */
	public static final int AUTHORITY = 2;

	/** The additional (fourth) section */
	public static final int ADDITIONAL = 3;

	/* Aliases for dynamic update */
	/** The zone (first) section of a dynamic update message */
	public static final int ZONE = 0;

	/** The prerequisite (second) section of a dynamic update message */
	public static final int PREREQ = 1;

	/** The update (third) section of a dynamic update message */
	public static final int UPDATE = 2;

	private static Mnemonic sections = new Mnemonic("Message Section",
			Mnemonic.CASE_LOWER);
	private static String[] longSections = new String[4];
	private static String[] updateSections = new String[4];

	static {
		sections.setMaximum(3);
		sections.setNumericAllowed(true);

		sections.add(QUESTION, "qd");
		sections.add(ANSWER, "an");
		sections.add(AUTHORITY, "au");
		sections.add(ADDITIONAL, "ad");

		longSections[QUESTION] = "QUESTIONS";
		longSections[ANSWER] = "ANSWERS";
		longSections[AUTHORITY] = "AUTHORITY RECORDS";
		longSections[ADDITIONAL] = "ADDITIONAL RECORDS";

		updateSections[ZONE] = "ZONE";
		updateSections[PREREQ] = "PREREQUISITES";
		updateSections[UPDATE] = "UPDATE RECORDS";
		updateSections[ADDITIONAL] = "ADDITIONAL RECORDS";
	}

	private Section() {
	}

	/** Converts a numeric Section into an abbreviation String */
	public static String string(int i) {
		return sections.getText(i);
	}

	/** Converts a numeric Section into a full description String */
	public static String longString(int i) {
		sections.check(i);
		return longSections[i];
	}

	/**
	 * Converts a numeric Section into a full description String for an update
	 * Message.
	 */
	public static String updString(int i) {
		sections.check(i);
		return updateSections[i];
	}

	/** Converts a String representation of a Section into its numeric value */
	public static int value(String s) {
		return sections.getValue(s);
	}

}
